The Problem That Kept Bothering Me
I wanted to grow my LinkedIn reach. The routine looks simple on paper.
Engaging with posts is easy.
Leaving thoughtful comments is easy.
Doing both every day is easy.
Keeping your patience through all of it is the part that breaks.
So I searched for auto-comment tools.
I found a wasteland of $49/month “basic” plans that rate-limit you to 20 comments per day. Other tools charged $17/month and stayed just as restrictive.
That is $1.63 per day for 20 comments. I did the math. The math made me sad.
The Tool Cemetery
I tested every one of them. Some promised huge results. Some had sleek landing pages and testimonials from “Sarah K., Marketing Director.”
The reality
Seven-day trials pressure you into a subscription.
Freemium plans are paid plans in disguise.
Rate limits get so strict that manual typing beats them.
Price tags cost more than the tool returns.
I was about to spend $250 on an annual subscription. Then I stopped and looked for one more option.
Butterfly
Butterfly is a Chrome extension with 4 ratings. Four is the real count.
I know what you’re thinking. “Only 4 reviews? Is this a scam?” I thought the same thing.
The extension works.
Links
GitHub: Butterfly Repository Chrome Store: Install Extension
What makes it different
It is not a SaaS platform that charges you monthly rent. It is a simple extension that uses your own free Gemini API key.
The setup
Install the extension.
Grab your free Gemini API key. Google gives you one.
Paste the key into the extension.
Add your custom prompt.
Start commenting.
The Free Models You Get
Google is generous with its API tier.
Gemini 2.5 Flash gives you 20 requests/day.
Gemini 2.5 Lite gives you more than that.
Gemini 3.0 Flash in preview is also available.
You can comment 20 or more times a day and spend nothing. If you need more, switch models. Each model carries its own free quota.
Why This Surprised Me
Full customization control
You write a custom master prompt in your own voice.
You select the comment tone.
You control the comment length.
You decide whether each comment ends with a question.
You use it on LinkedIn and on other platforms.
What you do not get
You get no monthly subscription emails.
You get no “upgrade to unlock more features” popups.
You get no artificial 5-comment-per-day limit.
You put no credit card on file.
The Catch
The only limit is the Gemini free tier rate limit. Paid tools charge $17-250/year for the same function and impose worse limits. Butterfly wins on both counts.
My Honest Take
I spent 3 hours on this search. I tested multiple tools. I got frustrated. I almost gave up.
Then I found Butterfly. It felt like a shortcut that everyone else forgot about.
Those expensive tools probably call the same API underneath. You pay them to sit in the middle.
Should You Try This
Try it if you match this list.
LinkedIn engagement eats too much of your time.
You avoid monthly subscriptions.
You accept a 2-minute setup process.
You want real control over your comments.
Then start with Butterfly before you pay another tool.
Final Thought
The best tool is not always the one with the biggest marketing budget. Sometimes it is a small extension with 4 Chrome reviews that works.
Thank you to the developer. You saved me $250 and many hours.
Have you tried Butterfly? Do you know other hidden tools like it? Drop a comment. I will probably auto-respond with this extension.
Related reading: The MrBeast Blueprint: YouTube Growth Tactics and How to Get Your First 10,000 Users Without Spam.
The pricing economics here are eye-opening. Any data privacy tradeoffs using your own key.
Here's the TL;DR version of this:
• Most LinkedIn engagement tools resell free APIs with markup.
• Pricing is disconnected from actual technical value delivered.
• Butterfly runs entirely on your own Gemini API key.
• This removes subscriptions while keeping full prompt control.
• The best tools often have the least marketing.